Interactive bash script

[mihaimyh]

I would like to use CliWrap to pass some strings to a bash script via standard input.
The script is like this:

#!/bin/bash
echo "Please type the user"
read -r user
echo "The user is: $user"
echo "Please type the password"
read -r password
echo "The password is: $password"

I've followed the example described here #191 but it seems the programs keeps waiting on the input for the user variable:

using var semaphore = new SemaphoreSlim(0, 1);
var buffer = new StringBuilder();

var stdin = PipeSource.Create(async (destination, cancellationToken) =>
{
    while (!cancellationToken.IsCancellationRequested)
    {
        await semaphore.WaitAsync(cancellationToken);
        var data = Encoding.UTF8.GetBytes(buffer.ToString());
        await destination.WriteAsync(data, 0, data.Length, cancellationToken);
    }
});

var cmd = stdin | Cli.Wrap("/tmp/test.sh");

await foreach (var cmdEvent in cmd.ListenAsync())
{
    if (cmdEvent is StandardOutputCommandEvent stdOutEvent)
    {
        Console.WriteLine(stdOutEvent.Text);

        // Detect if it's a prompt
        if (stdOutEvent.Text.Contains("user", StringComparison.InvariantCultureIgnoreCase))
        {
            // Write the response
            buffer.Clear();
            buffer.Append("user123");
            semaphore.Release();
        }

        else if (stdOutEvent.Text.Contains("password", StringComparison.InvariantCultureIgnoreCase))
        {
            // Write the response
            buffer.Clear();
            buffer.Append("pass123");
            semaphore.Release();
        }
    }
}

[mihaimyh]

I found what the problem is: the script was not properly consuming all of the input. Adding a newline character at the end of each input string, fixed the issue:

buffer.Clear();
buffer.Append("user123\n");
semaphore.Release();

buffer.Clear();
buffer.Append("pass123\n");
semaphore.Release();

[Tyrrrz]

Also, if your script always asks for username and password in the same order, you can just pipe them directly into the stdin like this:

var stdin =
    """
    user123
    pass123

    """;

var cmd = stdin | Cli.Wrap(...);

The approach you used is only necessary for dynamic prompts, i.e. when they don't always appear or when the order is inconsistent.

Either way, the script expecting a new line is a common behavior, and it was my mistake to not use AppendLine(...) instead of Append(...) – I edited the original comment (in #191) to fix that.

[citystrawman]

hello, may I know the computer system you use? I am trying to use cliWrap to execute bash script on windows system but it seems that the bash only recognize linux based ending signal which will lead the execution fail... I am searching how to solve it

[dengyakui]

Awesome, it works for me!